Year | Value | 2020 | 0.034 | 2019 | 0.038 | 2018 | 0.036 | 2017 | 0.022 | 2016 | 0.033 | 2015 | 0.032 | 2014 | 0.027 | 2013 | 0.051 | 2012 | 0.053 | 2009 | 0.027 | 2008 | 0.019 | 2004 | 0.022 | 2002 | 0.033 | 1998 | 0.033 | 1997 | 0.035 | 1996 | 0.024 | 1994 | 0.023 | 1992 | 0.027 | 1990 | 0.018 | 1984 | 0.025 | 1975 | 0.016 | 1970 | 0.017 | 1965 | 0.016 | 1960 | 0.011 |
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